1. Field of the Invention
The present invention is related to fire-retardant panels for building construction, and, more particularly, is related to panels that are interconnected to form a continuous fire-resistant diaphragm for a floor or a roof of a building.
2. Description of the Related Art
Prevention of fires is an important aspect of building construction and use; however, fires do occur within buildings, and is important that any such fire be confined so that the fire does not spread throughout the building. Since flames and heat from combustion tend to expand upwardly, it is particularly important to inhibit or retard the spread of a fire between floors and to inhibit or retard a fire from penetrating the roof and spreading to other structures.
Various techniques have developed for reducing the spread of fire, particularly with respect to high-rise buildings. For example, the floors of such buildings may comprise a layer of corrugated metal with a layer of concrete poured over the metal. The beams supporting such floors are generally heavy steel I-beams, or the like, with sprayed-on fire retardant material. Typically, the space between the ceiling of one story of the building and the floor of the next higher story is a significant percentage of the height of each story. Because of the weight of such structures and because of the equipment required to erect such structures, such techniques are not economically or mechanically practical for smaller buildings having one to a few stories, such as, for example, smaller office buildings, condominiums, apartments, and the like, which are generally constructed using more manual labor and less large equipment. Furthermore, the amount of extra space needed to accommodate the covered beams and thick floor may result in unacceptably tall building.
Other techniques used for construction of smaller buildings require the construction crews to perform additional steps. For example, rather than simply laying down underlayment panels on the beams (e.g., floor joists or roof rafters) of a building, the construction crew may lay down a pattern of fire-retardant strips before laying down the panels. The strips cover the gaps between adjacent panels so that flames or heat from a fire do not penetrate the gaps. The additional material and labor required to align and install the strips increase the cost of constructing the building.
In addition to retarding of the vertical spread of fire, underlayment panels attached to support beams are used to provide shear resistance capacity that substantially reduces the lateral shifting of a building during earthquakes, high winds and other events that exert significant forces on the building. The fire-resistant material used to retard the spread of fire is generally not suitable for providing shear resistance capacity. Thus, additional construction steps are needed to provide both fire-resistance and shear resistance capacity.